PDF(Pubmed)
Abstract：
In the situation of mass vaccination against COVID-19, few studies have reported on the early kinetics of specific antibodies (IgG/IgM/IgA) of vaccine breakthrough cases. There is still a lack of epidemiological evidence about the value of serological indicators in the auxiliary diagnosis of COVID-19 infection, especially when the nucleic acid results were undetectable. Omicron breakthrough cases post-inactivated vaccination (n = 456) and COVID-19-naive individuals with two doses of inactivated vaccination (n = 693) were enrolled. Blood samples were collected and tested for SARS-CoV-2 antibody levels based on the magnetic chemiluminescence enzyme immunoassay. Among Omicron breakthrough cases, the serum IgG antibody level was 36.34 Sample/CutOff (S/CO) (95% confidence interval [CI], 31.89 to 40.79) in the acute phase and 88.45 S/CO (95% CI, 82.79 to 94.12) in the recovery phase. Serum IgA can be detected in the first week post-symptom onset (PSO) and showed an almost linear increase within 5 weeks PSO. Compared with those of breakthrough cases, IgG and IgA titers of the postimmune group were much lower (4.70 S/CO and 0.46 S/CO, respectively). Multivariate regression showed that serum IgG and IgA levels in Omicron breakthrough cases were mainly affected by the weeks PSO (P < 0.001). Receiver operating characteristic ROC0 curve analysis showed that the area under the curve (AUC) was 0.744 and 0.806 when the cutoff values of IgA and IgG were 1 S/CO and 15 S/CO, respectively. Omicron breakthrough infection can lead to a further increase in IgG and IgA levels relative to those of the immunized population. When nucleic acid real-time PCR was negative, we would use the kinetics of IgG and IgA levels to distinguish the breakthrough cases from the immunized population. IMPORTANCE This study fills a gap in the epidemiological evidence by investigating the value of serological indicators, particularly IgG and IgA levels, in the auxiliary diagnosis of COVID-19 infections when nucleic acid results are undetectable. The findings reveal that among Omicron breakthrough cases, both IgG and IgA antibody levels exhibit significant changes. Serum IgG levels increase during the acute phase and rise further in the recovery phase. Serum IgA can be detected as early as the first week post-symptom onset (PSO), showing a consistent linear increase within 5 weeks PSO. Furthermore, receiver operating characteristic (ROC) curve analysis demonstrates the potential of IgG and IgA cutoff values as diagnostic markers. The study\'s conclusion underscores the importance of monitoring IgG and IgA kinetics in distinguishing Omicron breakthrough cases from vaccinated individuals. These findings contribute to the development of more accurate diagnostic approaches and help inform public health strategies during the ongoing COVID-19 pandemic.
摘要：
在COVID-19大规模疫苗接种的情况下，很少有研究报道疫苗突破病例的特异性抗体（IgG/IgM/IgA）的早期动力学。血清学指标在COVID-19感染辅助诊断中的价值尚缺乏流行病学证据,尤其是当核酸检测不到结果时。纳入了灭活疫苗接种后的Omicron突破病例(n=456)和接受两剂灭活疫苗接种的COVID-19初治个体(n=693)。收集血液样品并基于磁化学发光酶免疫测定法测试SARS-CoV-2抗体水平。在Omicron突破案例中，血清IgG抗体水平为36.34样品/切除（S/CO）（95%置信区间[CI]，在急性期为31.89至40.79），在恢复期为88.45S/CO（95％CI，82.79至94.12）。血清IgA可以在症状发作后（PSO）的第一周检测到，并且在PSO的5周内显示出几乎线性的增加。与突破性案例相比，免疫后组的IgG和IgA滴度低得多(4.70S/CO和0.46S/CO,分别)。多因素回归分析显示，Omicron突破病例血清IgG和IgA水平主要受PSO影响（P<0.001）。受试者工作特征ROC0曲线分析表明，当IgA和IgG的截止值分别为1S/CO和15S/CO时，曲线下面积（AUC）分别为0.744和0.806，分别。Omicron突破感染可导致IgG和IgA水平相对于免疫群体的水平进一步增加。当核酸实时PCR为阴性时，我们将使用IgG和IgA水平的动力学来区分突破性病例和免疫人群。重要性本研究通过调查血清学指标的价值，填补了流行病学证据的空白。特别是IgG和IgA水平，当核酸结果检测不到时，在COVID-19感染的辅助诊断中。研究结果表明，在Omicron突破案例中，IgG和IgA抗体水平均表现出显着变化。血清IgG水平在急性期增加，在恢复期进一步上升。血清IgA可以早在症状发作后（PSO）的第一周检测到，在5周内显示一致的线性增加PSO。此外，受试者工作特征(ROC)曲线分析证明了IgG和IgA截止值作为诊断标志物的潜力。该研究的结论强调了监测IgG和IgA动力学在区分Omicron突破病例与接种疫苗个体中的重要性。这些发现有助于开发更准确的诊断方法，并有助于在正在进行的COVID-19大流行期间为公共卫生策略提供信息。
